Improvement in the manufacture of paper from wood



UNITED STATES PATENT OFFICE.

STEPHEN M. ALLEN, OF \VOBURN, MASSACHUSETTS.

IMPROVEMENT IN THE MANUFACTURE OF PAPER FROM WOOD.

To all whom it may concern:

Be it known that I, STEPHEN M. ALLEN, of Woburn, county of Middlesex, State of Massachusetts, have invented a new and improved method of preparing paper-stock from woody fibers-such as cotton-wood, basswood, poplar, whitewood, cane, and other woody matter of like fibrous substances by a combined chemical and mechanical process and I hereby declare that the following is a full, clear, and exact description of my method or process.

Woody fiber or the fiber of trees, shrubs, &c., as distinguished from the fiber connected with the bark of plants or coverings of seed-plants, like flax, hemp, or cereals, &c., have many valuable uses aside from those usually applied. Among these is that of its application to the production of paper-stock. While the structure of the ultimate fiber is very much the same in solid woody fiber as that of the fiber attached to the bark of plants, the method of treating the same is very different. The fiber connected with the bark of plants is held together almostentirely byaglutinous substance soluble under proper circumstances in warm water and alkalies, so that when removed the fiber is easily separated and fibrilized. That of wood, on the other hand, while possessing the same or an analogous glutinous substance for a cementing purpose, the fibrils themselves are mechanically wrought together, so that if the glutinous matter be removed the fibers would still hold strongly together. Thus it will be seen that while the fibrils of flax and hemp of from one to two inches long can be separated after the gummy matter is removed, those of the fiber of bass-wood, whitewood, and the like cannot be so separated even after the glutinous matter has been removed. The peculiar interlacing of the fibrils of wood is partially shown in birds-eye maple, where the innumerable curlings and twistings are quite perceptible to the naked eye. The circulating action or capillary movement of the juices in the flax or hemp and the woodfibers is also different. In the former they are caused to pass through the tubes of the fibrils, while in the latter it is between and through the little cells formed by the fibrils in their interlacings that the sap circulates.

Two difficulties arise in making paper-pulp from either woody fiber or flax, hemp, or like substancesviz., the separation of the fibrils and the extraction of the gums and glutinous matter that surrounds the fiber of either. If this glutinous matter be not removed, the fiber cannot be bleached except at such strength of chlorine and acids as nearly to destroy the fiber, while the separation of the fiber by the usual process of grinding the pulp would pulverize rather than tibrilize the filaments.

Having thus stated the difficulties that are encountered in making paper from wood, I shall now proceed to describe my process of making paperpulp and paper from woody fiber.

I take bass-wood, cotton-wood, poplar,whitewood, willow, birch, white pine, and, in fact, nearly all the varieties of wood found in the United States, except birds-eye maple and pitch-pine, and saworcutthemup to convenient lengths for splitting into pieces of the length ordinarily used for shingles. I then crush the same between rollers or otherwise in such a way as to preserve the integrity of the fiber in its longitudinal direction, and afterward place the woodyfiber thus prepared in .a retort or boiler and subject the same to a series of steepings and washings in warm Water, with or without alkaline or acid solutions, at differenttemper atures of heat. The first steeping I effect at about 105 Fahrenheit, after which the fiberis rinsed or washed. The second at about 140 after which it is again rinsed or washed. For the third steeping I raise the temperature to about 170, after which the same is again rinsed or washed. The mass may then be boiled until properly prepared for bleaching and grinding. When bleached and ground the pulp may be mixed with some other fiber or used plain in the manufacture of paper.

From the above it will be seen that the main object I have in view is the preservation of the length of fiber in the wood when fibrilized, so that it may be long enough for any kind of paper. The efiect of steeping crushed or cut woody fiber prepared as before described in warm wateroralkalies at different temperatures is to dissolve the glutinous and resinous matter contained in the wood, and which is readily dissolved at different temperatures below the boiling-point, but which coagulates or crystallizes when boiled. Thus by alternately steeping and washing the obnoxious elements are removed, so that the filaments of wood will nating steeping and washing the same at infibrilize instead of pulverize, and thus make a creased temperatures, and finally boiling,

soft fiber sufficiently strong and fine for paper,

grinding, and bleaching the same, the whole While it Willbleach readily and grind well in in succession, substantially asherein described.

from wood by performing the operations of cutting the Wood in suitable lengths, crushing it in such manner as to preserve the integrity of the fiber in its longitudinal direction, alter- In testimony whereofI have signed my name to this specification before two subsoribin g wit- HGSSGS.

STEPHEN M. ALLEN.

Witnesses L. BURNETT, HIRAM WELLINGTON. 

